Walks on uncountable ordinals and non-structure theorems for higher Aronszajn lines

Fuente: arXiv
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Auteurs principaux: Inamdar, Tanmay, Rinot, Assaf
Format: Preprint
Publié: 2024
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author Inamdar, Tanmay
Rinot, Assaf
author_facet Inamdar, Tanmay
Rinot, Assaf
contents It is proved that if there is an $\aleph_2$-Aronszajn line, then there is one that does not contain an $\aleph_2$-Countryman line. This solves a problem of Moore and stands in a sharp contrast with his Basis Theorem for linear orders of size $\aleph_1$. The proof combines walks on ordinals, club guessing, strong colourings of three different types, and a bit of finite combinatorics. This and further non-structure theorems for Aronszajn lines and trees are established for successors of regulars, successors of singulars, as well as inaccessibles.
format Preprint
id arxiv_https___arxiv_org_abs_2410_08757
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Walks on uncountable ordinals and non-structure theorems for higher Aronszajn lines
Inamdar, Tanmay
Rinot, Assaf
Logic
Primary 03E02, 03E75, 06A05. Secondary 03E05
It is proved that if there is an $\aleph_2$-Aronszajn line, then there is one that does not contain an $\aleph_2$-Countryman line. This solves a problem of Moore and stands in a sharp contrast with his Basis Theorem for linear orders of size $\aleph_1$. The proof combines walks on ordinals, club guessing, strong colourings of three different types, and a bit of finite combinatorics. This and further non-structure theorems for Aronszajn lines and trees are established for successors of regulars, successors of singulars, as well as inaccessibles.
title Walks on uncountable ordinals and non-structure theorems for higher Aronszajn lines
topic Logic
Primary 03E02, 03E75, 06A05. Secondary 03E05
url https://arxiv.org/abs/2410.08757